# encoding=utf-8
from tkinter import *

class Calculator:
    def __init__(self, pwindow):
        self.pwindow = pwindow
        self.num1 = 0
        self.num2 = 0
        self.sign = None  # 运算符号
        self.if_equal = None  # 判断输入显示之前是否已进行过运算
        self.init_pwindow()

    def init_pwindow(self):
        """父窗口相关配置"""
        self.pwindow.title('计算器')  # 窗口名
        self.pwindow.geometry('200x300+10+10')  # 设置窗口的大小以及在屏幕上的位置

        # 设置按钮
        self.button_1 = Button(self.pwindow, text=1, width=5, command=lambda: self.show_num(1))
        self.button_1.grid(row=1, column=0)
        self.button_2 = Button(self.pwindow, text=2, width=5, command=lambda: self.show_num(2))
        self.button_2.grid(row=1, column=1)
        self.button_3 = Button(self.pwindow, text=3, width=5, command=lambda: self.show_num(3))
        self.button_3.grid(row=1, column=2)
        self.button_4 = Button(self.pwindow, text=4, width=5, command=lambda: self.show_num(4))
        self.button_4.grid(row=2, column=0)
        self.button_5 = Button(self.pwindow, text=5, width=5, command=lambda: self.show_num(5))
        self.button_5.grid(row=2, column=1)
        self.button_6 = Button(self.pwindow, text=6, width=5, command=lambda: self.show_num(6))
        self.button_6.grid(row=2, column=2)
        self.button_7 = Button(self.pwindow, text=7, width=5, command=lambda: self.show_num(7))
        self.button_7.grid(row=3, column=0)
        self.button_8 = Button(self.pwindow, text=8, width=5, command=lambda: self.show_num(8))
        self.button_8.grid(row=3, column=1)
        self.button_9 = Button(self.pwindow, text=9, width=5, command=lambda: self.show_num(9))
        self.button_9.grid(row=3, column=2)
        self.button_0 = Button(self.pwindow, text=0, width=5, command=lambda: self.show_num(0))
        self.button_0.grid(row=4, column=2)

        self.button_add = Button(self.pwindow, text='+', width=5, command=lambda: self.sign_num('+'))
        self.button_add.grid(row=4, column=0)
        self.button_add = Button(self.pwindow, text='-', width=5, command=lambda: self.sign_num('-'))
        self.button_add.grid(row=4, column=1)
        self.button_add = Button(self.pwindow, text='*', width=5, command=lambda: self.sign_num('*'))
        self.button_add.grid(row=5, column=0)
        self.button_add = Button(self.pwindow, text='/', width=5, command=lambda: self.sign_num('/'))
        self.button_add.grid(row=5, column=1)

        self.button_equal = Button(self.pwindow, text='=', width=5, command=self.equal_num)
        self.button_equal.grid(row=5, column=2)

        # 设置文本显示框
        self.text_1 = Text(self.pwindow, width=18, height=3)
        self.text_1.grid(row=0, column=0, columnspan=3)

    def show_num(self, num):
        """显示数字到显示框"""
        if self.if_equal:
            self.text_1.delete(1.0, END)
            self.if_equal = False
        self.text_1.insert(2.0, num)

    def sign_num(self, sign):
        """运算符号"""
        self.sign = sign
        self.num1 = self.text_1.get(1.0, END)
        self.text_1.delete(1.0, END)  # 清空显示框

    def equal_num(self):
        """等于号"""
        self.if_equal = True
        self.num2 = self.text_1.get(1.0, END)
        self.text_1.delete(1.0, END)
        count = 0
        if self.sign == '+':
            count = float(self.num1) + float(self.num2)
        elif self.sign == '-':
            count = float(self.num1) - float(self.num2)
        elif self.sign == '*':
            count = float(self.num1) * float(self.num2)
        else:
            count = float(self.num1) / float(self.num2)
        self.text_1.insert(1.0, count)


if __name__ == '__main__':
    parent_window = Tk()
    c = Calculator(parent_window)
    parent_window.mainloop()